When integrating electronic components, in particular integrated semiconductors (IC's), but also chip modules, displays, batteries, coils, capacitors, contact points etc. in polycarbonate (PC) based documents, there is, for instance for thin semiconductor structures, a problem of premature destruction or reduced of life time of the components during the lamination by thermal and mechanical overload or stress. In prior art methods of the above kind, for instance for producing PC smart cards by lamination of individual film layers, the positioning of a PC film is made directly over the chip. In the industrially established approach, the prepared card structures are pressed together under the simultaneous action of temperature and pressure to form a “quasi-monolithic” block. Since PC does not immediately soften due to its specific heat transfer coefficient and its relatively high glass temperature Tg, there is an increased mechanical pressure directly at the chip, this pressure leading in most cases to a mechanical destruction of the chip.
For avoiding this problem, it is known in the art to apply self-adhesive or elastic films on the electronic components, thus the PC films with interposed components, such as chips, can be combined to a card without a high risk of destruction of the component. Normally, these adhesive layers are a weak point of the card structure. Through the card edge, water vapor and air can easily enter and thus lead to a later delamination. Other environmental influences, in particular high temperatures, but also fast temperature changes may lead to that card splits open and cannot be used any longer. Furthermore, adhesive films with a thickness <50 μm can only difficultly or not at all be handled on an industrial scale, and are inflexible, when it is important, e.g., to fill up cavities. Similar considerations apply to components having diffractive structures, e.g. volume holograms. If the hologram is directly laminated with further PC films to form a card, this will happen under certain circumstances under visible and measurable losses of the representation quality of the hologram, in particular of the colors and the 3-dimensional appearance. Most volume holograms based on photopolymers have a softening point or glass temperature Tg of clearly below 150° C. If during the lamination the PC films being still hard at the beginning are pressed on the soft photopolymer of the hologram, the Bragg planes are displaced, and certain elements appear to be displaced in their wavelengths. For instance, green picture elements will become yellow picture elements etc. Further, in particular for volume holograms, the 3-dimensional appearance is clearly reduced, and the holograms seem to be rather flat and 2-dimensional and washed-out. These effects, too, are based on the problem that either the “hard” PC is placed on brittle surfaces and causes mechanical stress or deforms softer bodies, for instance made from a photopolymer, thus these components being impaired in their function.
From the document EP 0688839 A2, polycarbonates based on a geminally disubstituted dihydroxydiphenyl cycloalkane are per se known. In this prior art, such polycarbonates are used as binding agents of silk-screen printing inks. From this document can also be taken methods for making such polycarbonates. This document with its complete contents is hereby included in the scope of disclosure of the present application.